The small plane crashed into a lake on Sunday.
A plane crash in South Sudan killed 20 people, including an Anglican bishop and four foreigners, a regional official said, updating the toll.
Regional spokesman Taban Abel Aguek said 20 people died and three survived when a small plane crashed into a lake close to Yirol in the centre of the country on Sunday morning.
"Among the dead, 16 are South Sudanese nationals while four are foreigners including the pilot and the co-pilot, who are Sudanese. One Ugandan and an Ethiopian... also died in the crash," Abel said.
The Anglican Bishop of Yirol, Simon Adut, was among those killed as was a staff member of the South Sudanese Red Cross, while an Italian doctor and two children were among the survivors.
An official with the South Sudan Aviation Authority said investigations were underway but that overloading and bad weather may have led to the accident.
Abel said the regional governor had declared three days of mourning.